Retractable Injection Port

ABSTRACT

A cannula, for delivering a bolus of a pharmaceutically active agent to the posterior chamber of the eye, having an orifice disposed at the distal tip. The cannula is slidably disposed within a hypodermic needle. The sliding action of the cannula within the needle provides a means for trimming a formed bolus of a pharmaceutically active agent from the orifice of the cannula. In addition, the double wall formed by the cannula within the needle provides insulation from the cooler temperatures within the eye to allow for the delivery of phase transition substances.

RELATED APPLICATIONS

This application is a continuation-in-part of U.S. patent application Ser. No. 11/581,629 filed Oct. 16, 2006, U.S. patent application Ser. No. 11/581,630 filed Oct. 16, 2006, and U.S. patent application Ser. No. 11/581,591 filed Oct. 16, 2006.

FIELD OF THE INVENTION

The present invention relates to a single-use medical device and more particularly to an ophthalmic drug delivery device with a retractable injection port.

BACKGROUND OF THE INVENTION

Several diseases and conditions of the posterior segment of the eye threaten vision. Age related macular degeneration (ARMD), choroidal neovascularization (CNV), retinopathies (e.g., diabetic retinopathy, vitreoretinopathy), retinitis (e.g., cytomegalovirus (CMV) retinitis), uveitis, macular edema, glaucoma, and neuropathies are several examples.

These, and other diseases, can be treated by injecting a drug into the eye. Such injections are typically manually made using a conventional syringe and needle, or an infusion cannula. In the past, if a procedure required that a cannula be inserted into the eye, a trocar stick was required to pre-puncture the eye. In many cases, this was accomplished by having the cannula preinstalled around the trocar, so that, once the trocar had punctured the eye, the cannula would be slid into the puncture, and the trocar would then be removed. Problems would arise with respect to conditions requiring a cannula that cannot utilize a trocar due to cannula length or the injection location. In this scenario, the only available alternative is to pre-puncture the eye, remove the trocar, and then attempt to insert the cannula into the puncture wound. This procedure introduces significant risks, including but not limited to trauma to the eye at the incision site, increased risk of post-operative infection, and loss of intra ocular tissue and fluid since the eye is a pressurized globe. In addition, this requirement adds significant time to the overall procedure.

In addition, advancements have been made in the types of drugs used to treat the above mentioned, and other eye diseases. Specifically, several developments have been made utilizing phase transition or reagent/drug mixtures. In this procedure, a drug, or mixture, is heated in a delivery device, such as a syringe with needle, and delivered to the posterior chamber of the eye in an injectable state (liquid, gel or semi-solid). Once in the posterior chamber of the eye, the drug cools and solidifies. As the solid dissolves, the drug is delivered to the eye over an extended length of time greater than standard liquid injections, thereby reducing the frequency of required treatments. In such a procedure, it is desirable to have the drug introduced into the eye in a roughly spherical shape as a means of maximizing the drug delivery time. Use of prior art needles for such a treatment would result in a cylindrical or “worm shaped” solid being deposited in the eye. Such a shape has considerably greater surface area, and, as such, would dissolve faster eliminating the benefits of time-released delivery.

There are several commercial needle styles involving holes distal from the tip such as the SPROTTE® spinal needle sold by Dyna Medical Corporation of London, Ontario, Canada. Many of these are designed for irrigation and aspiration applications. Of those commercialized, there are none specifically associated with injectors that are designed to deliver melted or phase transition materials. In addition, none of the commercially available needle styles offer a means to trim the injected bolus from the cannula body. This may result in the drug being deposited in the sclera when the needle or cannula is removed from the eye.

Accordingly, it would be desirable to have a hypodermic needle that will be able to penetrate the eye without the need of pre-puncturing, allows for a suture-less procedure, provides insulation of the drug from the cooler temperature of the eye, and provides a means to trim a roughly spherical shaped bolus from the orifice upon drug delivery. A cannula slidably disposed within a hypodermic needle could be used to provide a means to trim the deposited bolus from the cannula body. In addition, the double wall layer created by the needle and the cannula could provide insulation of a melted drug from the cooler temperature of the eye. The device could also be such that the needle is slidably disposed within the cannula resulting in similar benefits. Such a system provides numerous benefits over prior art injectors.

SUMMARY OF THE INVENTION

In one embodiment, consistent with the principles of the present invention, the present invention is a cannula, for delivering a bolus of a pharmaceutically active agent to the posterior chamber of the eye, having an orifice disposed at the distal tip. The cannula is slidably disposed within a hypodermic needle. The sliding action of the cannula within the needle provides a means for trimming a formed bolus of a pharmaceutically active agent from the orifice of the cannula. In addition, the double wall formed by the cannula within the needle provides insulation from the cooler temperatures within the eye to allow for the delivery of a phase transition drug formulation.

In another embodiment, consistent with the principles of the present invention, the present invention is a cannula, having an orifice disposed at the distal tip, and having a hypodermic needle slidably disposed within.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are intended to provide further explanation of the invention as claimed. The following description, as well as the practice of the invention, set forth and suggest additional advantages and purposes of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate several embodiments of the invention and together with the description, serve to explain the principles of the invention.

FIG. 1 is a cross sectional view of a retractable injection port according to a first embodiment of the present invention.

FIG. 2 is a cross sectional view of a retractable injection port according to a second embodiment of the present invention.

FIG. 3 is a cross sectional view of a retractable injection port according to a third embodiment of the present invention.

FIG. 4 is a cross sectional view of a disposable tip segment of a heated syringe that could be used in conjunction with the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference is now made in detail to the exemplary embodiments of the invention, examples of which are illustrated in the accompanying figures. Wherever possible, the same reference numbers are used throughout the figures to refer to the same or like parts.

FIG. 1 is one view of an ophthalmic medical device including a needle and a cannula according to an embodiment of the present invention. In FIG. 1, medical device 10 includes cannula 12 and needle 14. Cannula 12 includes closed distal tip 16 and orifice 18. Needle 14 includes beveled tip 20.

Cannula 12 is slidably disposed within needle 14 and may be fluidly connected to any appropriate mechanism for storage and delivery of a pharmaceutically active agent, such as a syringe or IV tube, but is most preferably fluidly coupled to a heated syringe as illustrated in FIG. 4. A pharmaceutically active agent, typically a drug suspended in a phase transition compound, is contained within the storage and delivery mechanism. The phase transition compound is in a solid or semi-solid state at lower temperatures and a liquid state at higher temperatures. Such a compound can be heated to a lower viscous liquid state and injected into the eye where it forms a bolus that erodes over time.

In the embodiment of FIG. 4, tip segment 210 includes plunger interface 420, plunger 415, dispensing chamber housing 425, tip segment housing 217, temperature control device 450, thermal sensor 460, needle 14, dispensing chamber 405, interface 530, and tip interface connector 453. In tip segment 210, plunger interface 420 is located on one end of plunger 415. The other end of plunger 415 forms one end of dispensing chamber 405. Plunger 415 is adapted to slide within dispensing chamber 405. The outer surface of plunger 415 is fluidly sealed to the inner surface of dispensing chamber housing 425. Dispensing chamber housing 425 surrounds the dispensing chamber 405. Typically, dispensing chamber housing 425 has a cylindrical shape. As such, dispensing chamber 405 also has a cylindrical shape.

Needle 14 is fluidly coupled to dispensing chamber 405. In such a case, a substance contained in dispensing chamber 405 can pass through needle 14 and into an eye. Temperature control device 450 at least partially surrounds dispensing chamber housing 425. In this case, temperature control device 450 is adapted to heat and/or cool dispensing chamber housing 425 and any substance contained in dispensing chamber 405. Interface 530 connects temperature control device 450 with tip interface connector 453.

Optional thermal sensor 460 provides temperature information to assist in controlling the operation of temperature control device 450. Thermal sensor 460 may be located near dispensing chamber housing 425 and measure a temperature near dispensing chamber housing 425 or may be located in thermal contact with dispensing chamber housing 425, in which case it measures a temperature of dispensing chamber housing 425. Thermal sensor 460 may be any of a number of different devices that can provide temperature information. For example, thermal sensor 460 may be a thermocouple or a resistive device whose resistance varies with temperature. Thermal sensor is also electrically coupled to interface 530 or other similar interface.

The components of tip segment 210, including dispensing chamber housing 425, temperature control device 450, and plunger 415 are at least partially enclosed by tip segment housing 217. In one embodiment consistent with the principles of the present invention, plunger 415 is sealed to the interior surface of dispensing chamber housing 425. This seal prevents contamination of any substance contained in dispensing chamber 405. For medical purposes, such a seal is desirable. This seal can be located at any point on plunger 415 or dispensing chamber housing 425.

Cannula 12 is adapted to deliver a pharmaceutically active agent into an eye. Cannula 12 may be of any commonly known configuration, and may be made from any appropriate material. Preferably, cannula 12 is designed such that its thermal characteristics are conducive to the particular drug delivery application. For example, when a heated drug is to be delivered, cannula 12 may be relatively short (several millimeters) in length to facilitate proper delivery of the drug due to thermal characteristics. Distal tip 16 and orifice 18 of cannula 12 may be of any commonly known configuration. Preferably, distal tip 16 is blunt or rounded, and orifice 18 is located on a side wall 22 of cannula 20. In an alternative embodiment, distal tip 16 is flat, and orifice 18 is disposed at the distal tip, as shown in FIG. 2. Orifice 18 may be of any appropriate shape, but most preferably comprises a geometry conducive to producing a roughly spherical bolus of a pharmaceutically active agent.

Needle 14 is hollow with cannula 12 slidably disposed within. Needle 14 is adapted to deliver a pharmaceutically active agent to an eye. Needle 14 may be of any commonly known configuration, and may be made from any appropriate material, such as surgical stainless steel. Preferably, needle 14 is designed such that its thermal characteristics are conducive to the particular drug delivery application. For example, when a heated drug is to be delivered, needle 14 may be relatively short (several millimeters) in length to facilitate proper delivery of the drug due to thermal characteristics. Beveled tip 20 may be of any appropriate geometry, but is most preferably an angled cut hypodermic ground bevel.

During insertion, cannula 12 is initially entirely disposed within needle 14. Beveled tip 20 of needle 14 is used to puncture the sclera of an eye. Once needle 14 has entered the posterior chamber of the eye, it is partially withdrawn exposing cannula 12. The pharmaceutically active agent is then expressed into the eye via orifice 18. The pharmaceutically active agent could be a heated phase transition compound, in which case a roughly spherical bolus 24 will be created at orifice 18. In addition, the double wall created by needle 14 and cannula 12 insulates the heated compound from the cooler temperatures within the eye. Once deposited in the eye, bolus 24 may then be trimmed from cannula 12 by withdrawing cannula 12 into needle 14.

In another embodiment of the present invention, shown in FIG. 3, needle 140, which is similar to needle 14, is slidably disposed within cannula 120, which is similar to cannula 12. During operation, cannula 120 is initially withdrawn exposing tip 200 of needle 140. Needle 140 pierces the sclera and guides cannula 120 into the posterior chamber of the eye. Needle 140 is then withdrawn leaving cannula 120 inserted into the eye. A pharmaceutically active agent is then expressed into the eye via orifice 180 which is located at distal end 160 of cannula 120.

From the above, it may be appreciated that the present invention provides a cannula, for delivering a bolus of a pharmaceutically active agent to the posterior chamber of the eye, having an orifice disposed at the distal tip. The cannula is slidably disposed within a hypodermic needle. The sliding action of the cannula within the needle provides a means for trimming a formed bolus of a pharmaceutically active agent from the orifice of the cannula. In addition, the double wall formed by the cannula within the needle provides insulation from the cooler temperatures within the eye to allow/improve the delivery of phase transition substances.

Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims. 

1. A retractable injection port comprising: a hypodermic needle having a sharpened distal tip; and a cannula, slidably disposed within the needle, the cannula having an orifice disposed at a distal end, the orifice fluidly coupled to a mechanism for delivering a substance; wherein the needle and the cannula provide insulation to the substance contained therein.
 2. The port of claim 1 wherein the orifice is disposed in a side wall of said cannula.
 3. The port of claim 1 wherein the distal end of the cannula is rounded.
 4. The port of claim 1 wherein the distal end of the cannula is flat.
 5. The port of claim 1 wherein the mechanism is a syringe having a heated dispensing chamber.
 6. The port of claim 1 wherein the substance comprises a phase transition compound.
 7. The port of claim 1 wherein sliding said needle over said orifice trims a bolus of said substance.
 8. A retractable injection port comprising: a cannula having an orifice disposed at a distal tip; and a hypodermic needle slidably disposed within the cannula.
 9. A retractable injection port comprising: a hypodermic needle having a sharpened distal tip; and a cannula, slidably disposed within the needle, the cannula having an orifice disposed at a distal end, the orifice fluidly coupled to a syringe having a heated dispensing chamber; wherein the needle and the cannula provide insulation to a heated phase transition compound.
 10. The port of claim 9 wherein the orifice is disposed in a side wall of said cannula.
 11. The port of claim 9 wherein the distal end of the cannula is rounded.
 12. The port of claim 9 wherein the distal end of the cannula is flat.
 13. A method for delivering a substance into an eye comprising the steps of: providing a retractable injection port having a cannula slidably disposed within a hypodermic needle, said needle disposed at a distal end of a heated syringe; piercing the sclera of said eye with said hypodermic needle; partially withdrawing said needle to expose said cannula; expressing substance into said eye through an orifice disposed at a distal tip of said cannula; trimming said substance from said cannula by withdrawing said cannula into said needle.
 14. The method of claim 13 wherein said orifice is disposed in a side wall of said cannula.
 15. The method of claim 13 wherein said orifice is disposed in a distal tip of said cannula.
 16. The method of claim 13 wherein said substance comprises a heated phase transition compound.
 17. The method of claim 16 wherein said phase transition compound is insulated by said needle and said cannula. 